Method of reducing metals and making alloys



Patented @et. 17, 11922.

UNTTED STATES PATENT @FFHQK WALTER BIRKETT HAITILTON, Q15 LANCASTER, AND TEIQMAS ALLEN EVANS,

MANCHESTER, ENGLAND.

METHOD OF REDUCING: METALS AND MAKING ALLOYS.

I70 Drawing.

. To all whom it may concern:

Be it knownthatwe, WALTER Bmnn'r'r HAMILTON and THoMAs ALLEN EVANS, subjects of the King of England, residing at Lancaster and Manchester, England, respectively, have invented new and useful Improvements in Methods of Reducing Metals and Making Alloys, of which the following is a specification.

We have discovered that it chromium ore (chromite) be introduced, together with aluminum, into a suitable slag on top of molten iron in a furnace, that the entire body of the ore, with all its difiicultly-fusible components (magnesia, etc), will be fused; and that the chromium oxide and iron oxide con tained therein will be reduced; and that the chromium and iron so formed will descend into the molten metal, while the other components slag; and that the slagnot only acts as a flux which promotes the fusion of the ore, but protects the molten metal beneath it from contamination by the "carbon electrodes (if an electric furnace be used) or from contamination by the heating gases (if a fulnace of the open-hearth type be used) and that it also acts after reduction has taken place as a refining agent 'for the molten metal.

By this process, for example, rustless iron substantially free of carbon may be cheaply produced containing any desired percentage of chromium; or rustless steel; may e cheaply produced containing any desired percentage of chromium and carbon. The former has technical advantages over the latter in that it is rust-resisting without hardening and may be readily drawn and Worked, while the latter to be rust-resisting must be hardened and cannot be readily drawn and worked.

In the practice of our invention the metal is brought to a molten condition, and a suitable slag is formed on the top thereof. The ore and the thermo-reducing agent are I added to the slag when the. temperature of the slag is such that, with the calories enerated by the exothermic reaction of t ese a materials, it will meltthe ore. Thereupon the oxide of metal is reduced and by gravity the metal separates from the molten slag and descends into the molten metal beneath,

of the ore will'be retained in the.

Application filec'tmay 28!, 19%. Serial Ito. 563,020.

bying iron (with or without pounds of iron scrap (substantially carbonfree or containing any amount otc'arbon) and 8% or 10% limestonewhich is brought I to a molten condition. The first slag formed thereon is-completely removed to eliminate impurities which otherwise would be reduced back nto the iron. The molten metal is then covered with, preferably, a mixture .of 60 lbs. limestone 18 lbs. fluor spar and -12 lbs. mill-scale. lleat is applied until the reception slag formed thereby is brought to a molten condition. When the slag is brought to a temperature suiiicient to efi'ect reduction, 450 pounds of chromite (chromium ore), preferably ground and calcined, with approximately 120 pounds of aluminum, are gradually added to the slag. The reaction between the oxides of the metals and the reduc agent is, as is Well known, exothermic. ithin a few minutes after the completion of the addition of the ore and thermo-reducing agent, the reduction ofthe metals will be completed and the reduced metals will have entered the molten mass beneath the slag. It is desirable to continue the application of heat for a short chromite does not give the amount of manganese desired in the finished iron, manganese ore also may be added to the flux.

In the above example, if the furnace has been ehargedwith scrap iron substantially carbon-free, the resulting product will be a chromium-iron .alloy containing approximately twelve per cent. chromium and less than 0.14% carbon. If the furnace has been .80 approximately pure metal may be made by this process if the ore added contains, practically speaking, the oxide of only one metal, by charging the furnace with the same metal. So bronze may be made by this metal which consists in charging a furnace process by charging the furnace with copper and adding to the molten slag tin ore. So aluminum bronze may be made by this process by charging the furnace with aluminum and adding to the molten slag copper ore.

It is obvious that other alloys may be made by this process, but the above examples are suflicient for a full understanding of the same.

Instead of usingaluminum as the reducing agent, other thermo-reducing agents such as silicon, magnesium, or the like may be used. Instead of'using a lime flux in which the reduction takes place, other suitable fluxes not reduced by 'the reducing agent employed may be used:

The word oxide herein will be understood to include chlorides, fluorides, and the like, not volatilized in the presence of the reagent employed. The word ore herein will be understood to include other compositions of metallic oxides and refuse matter, such, for example, as exist in certain dumps.

Having now described our invention, we claim! 1,. The process of making rust-resisting metal which consists in charging a furnace with iron, melting the same, forming a slag thereon and adding to said slag ore containing chromium oxide in the presence of a thermo-reducing agent, whereby the ore is fused, the oxide is reduced and the resultin chromium descends into the molten meta beneath the slag.

2. The process of making rust-resisting with iron and a slag-formin material, melting the same, removing the s' ag thus formed, adding to the molten metal material to form a reception slag and adding to said reception slag ore containing chromium oxide in the presence of a thermo-reducing agent, whereby the ore is fused, the oxide is reduced and the resulting chromium descends into the molten metal beneath the slag.

3. The process of making alloys vwhich consists in charging a furnace with a suitable metal, melting the same, forming a slag thereon and adding to said slag ore containing a suitable metal oxide in the presence of a thermo-reducing agent, whereby the ore is fused the oxide is reduced and the resulting metal descends into the molten metal beneath the slag.

4:. The process of making an alloy containing chromium and iron which consists in charging a furnace with a suitable metal, melting the same, forming a slag thereon and adding to said slag ore containing chromium and iron oxides in the presence of a thermo-reducing agent, whereby the ore isfused, the oxides are reduced, and the resulting metals descend into the molten metal beneath the slag. f

5. The process of reducing metal and separating it from ore which consists in charging a furnace with a suitable metal, melting the same, forming a slag thereon and adding to said slag ore containing a suitable metal oxide in the presence of a reducing agent exothermic in its action with respect to said metal oxide, whereby the oreis fused,

the oxide is reduced and the resulting metal descends into the molten metal beneath the slag.

able metal, melting the same, forming a slag thereon, addingto said'sla ore containing a suitable metal oxide inf t e presence of a reducing agent exothermic in its actionwith respect to said metal oxide, whereby the ore I is fused, the oxide is reduced and the resulting metal descends into the molten metal beneath the slag, and maintaining the temperature of the slag until the molten metal is refined.

7 The process of reducing ferrous metals and separating them from ore, which consists in adding to molten slag in a furnace ore containing a suitable metal oxide and a the oxide is reduced and the resulting metal descends beneath the slag.

In testimony whereof we havesigned our 12c names. to this specification.

'WALTER BIRKETT HLTON.

THOMAS ALLEN EVANS.

6. The process of making'alloys which consists in charging a furnace with a suit- 

